In Matthew 28:19, Jesus said to “go and make disciples of all nations.” But nearly half of young Christians in the U.S. believe that’s an immoral act, a new report from Barna Group reveals.

While 96 percent of practicing U.S. Christians in the millennial generation agree that “being a witness about Jesus” is part of their faith, 47 percent say it is wrong to evangelize those of other religions.

Barna defines practicing Christians as those who self-identify as Christian, agree strongly that faith is an important part of their lives, and have attended church within the past month.

Millennials (those born between 1984 and 1998, by Barna’s definition) aren’t the only churchgoers questioning the morality of evangelism. Among all practicing Christians, 27 percent say it’s wrong for Christ followers to share their beliefs with people of other faiths.

Nevertheless, 79 percent of practicing Christians strongly agree — and more than 90 percent at least somewhat agree — that coming to know Jesus is the best thing that could ever happen to a person.

Seventy-nine percent of practicing Christians strongly agree that coming to know Jesus is the best thing that could ever happen to a person.

Despite their reluctance to share the gospel, millennials are more likely than older generations to say they are gifted at talking about their faith (73 percent of millennials, compared to 66 percent of Gen X, 59 percent of baby boomers, and 56 percent of elders (those born before 1946). Yet millennials are slightly less likely than older adults to say they know how to answer questions about Christianity (86 percent versus 92 percent of boomers).

Meanwhile, 22 percent of non-Christians — including 29 percent of people of other religions, 32 percent of atheists and agnostics, and 8 percent of “nones” — say they would like to learn more about Christianity and what it would mean for their lives. Among those who express an interest in exploring Christianity, a plurality (41 percent) say they would prefer to get the information from a one-on-one conversation with a Christian, rather than from a church service or event (30 percent), or from a small group of mostly non-Christians exploring faith together (29 percent).

Barna notes that starting conversations can be difficult for young people, particularly since many equate disagreement with disrespect. In fact, 4 in 10 practicing Christian millennials saying that “if someone disagrees with you, it means they’re judging you.” By comparison, only 22 percent of Gen X, 9 percent of boomers, and 11 percent of elders say this. This may help explain the reticence of young Christians to talk about Jesus in an increasingly secular nation. It also highlights the challenges today’s churches face.

“Leaders who want to equip Christians today to share Jesus with non-believers face an unusual challenge: to first ‘evangelize’ Christians on the importance — and morality — of evangelism,” the Barna report says.

Romans 10:13–14 is a good place to start: “‘Everyone who calls on the name of the Lord will be saved.’ But how can they call on him to save them unless they believe in him? And how can they believe in him if they have never heard about him? And how can they hear about him unless someone tells them?” (NLT).